1. Item 4: Report from the GSICS Research Working group (GRWG)
Special Issue of the IEEE TGRS on “Inter-Calibration of Satellite Instruments”:
Special Issue of the IEEE TGRS on “Inter-Calibration of Satellite Instruments”:
12 November 2018
Item 4: Report from the GSICS Research Working group (GRWG)
Tim Hewison
(EUMETSAT) (GRWG Chair)

2. Overview Highlights of 2015 Annual Meeting Other progress in 2014/15
Sub-Group News
Issues for Executive Panel & GSICS Users
Potential Future GSICS Deliverables
GRWG Chair & Vice-chair
2016 Annual meeting
Issues for GSICS Users

3. Overview Highlights of 2015 Annual Meeting Other progress in 2014/15
Sub-Group News
Issues for Executive Panel & GSICS Users
Potential Future GSICS Deliverables
GRWG Chair & Vice-chair
2016 Annual meeting
Issues for GSICS Users

4. Overview of Agenda or 2015 GRWG/GDWG Annual Meeting
Monday: Opening Ceremony + Mini Conference
Tuesday: Chairs’ + Agency Reports + Briefings
Wednesday: GRWG: VIS/NIR: DCC + Lunar
Wednesday: GDWG
Thursday: GRWG: IR (nb no UV or MW this time)
Thursday: GDWG
Friday am: GRWG + GDWG
Friday pm: Wrap-up (Plenary)
All presentations online on GSICS Wiki

5. Selected Highlights Opening/Closing Ceremonies
Definition of GSICS Deliverables
Inter-Calibration Product Development for Geostationary Imagers
Globalisation of GSICS
Full minutes available in Word Online

7. GSICS Corrections for GEO-LEO IR
In 2015, 6 GPRCs are preparing for their GEO-LEO IR GSICS products to enter new modes:
EUMETSAT and NOAA -> Operational mode
JMA -> pre-operational mode
ISRO, CMA, KMA -> demonstration mode
For the first time we will be able to inter-calibrate the geostationary ring to the same reference!

8. Linking the GEO ring
Schematic Example of GEO and LEO Earth Observing Satellites
Showing GEO sub-satellite longitude and equator crossing time for sun-synchronous LEO satellites

9. GEO-LEO IR - Hyperspectral SNO
Simultaneous near-Nadir Overpasses
of GEO imager and LEO sounder
Select Collocations
Spatial, temporal and geometric thresholds
Schematic illustration of the geostationary orbit (GEO) and polar low Earth orbit (LEO) satellites and distribution of their collocated observations.

10. Linking the GEO ring GSICS Corrections for GEO-LEO IR
All using Metop/IASI as hyperspectral references
Solid lines = Pre-Operational
Dashed lines = Demonstration
Dotted lines = Prototype

11. GEO-GEO IR – Broadband SNO
Simultaneous near-Nadir Overpasses
of GEO imager pairs
Select Collocations
Spatial, temporal and geometric thresholds
Narrow longitudinal strip of collocations
Allows continuous comparisons 24/7
Investigate midnight calibration problems
Non-identical Spectral Responses
Need Spectral Band Adjustment Factor
Based on IASI observations
Or reference profiles + RTMs
Example Image of Meteosat μm Channel Grey area shows collocated MSG2-MSG1 pixels

12. Linking the GEO ring GEO-GEO Comparisons
Based on collocated observations
GEO imager pairs
Need SBAFs

13. Linking the GEO ring Comparing GEO-LEO and GEO-GEO Differences
To Validate Uncertainty estimates
Ensure consistency
Generate global L2 products

14. Strategy for closing the GEO Ring
First step: Identify one date which is common to all GEOs
(without stray light or midnight effect)
Second step: to investigate the GEO-GEO comparison across the GEO ring.
Rob mentioned that the climate community would test the result of this work.
Action: Tim to ask ECMWF for double differencing of geostationary ring.
Action: IMD/ISRO to contact the IMD NWP and NCMRWF about the same topic.
Action: Tim to conduct a survey to identify a date among GPRC so that they produce the GSICS corrections for that date and provide them to Dave.
Dave suggests taking 0/3/ 6/9 GMT for that date.
Action: Dave to report on the analysis of these data.
Action: Tim to provide SBAF tool to support this analysis
CMA are interested to compare the FY-2 observations to other instruments.

15. GEO-LEO VIS/NIR Currently two main activities on-going:
Inter-calibration of GEO imagers with MODIS using Deep Convective Clouds as transfer target
Lunar calibration and using the Moon for inter-calibration.
SEVIRI L1.0 image
10.8μm TB [K]
MTSAT-2 DCC detection T04
Meteosat-9/VIS06 Bias Change
wrt ROLO Model Lunar Irradiance
(after phase angle correction)

16. DCCs NRTC – 30 days K-K0 MODE MODE – No saturation MEAN
SKEWNESS + smoothed over 30 days
MODE – No saturation
Number of DCCs
MEAN
MEAN – No saturation
K-K0
KURTOSIS + smoothed over 30 days

17. DCCs
Seasonality affects differently GEO imagers (amplitude, periodicity, presence of a seasonal signal, etc.)  Various methods to address it:
EUMETSAT: approach based on estimating seasonal factors + choice of a model  Multiplicative: Seasonalized = Deseasonalized * Seasonal factors
NOAA: seasonal cycle removed using a prediction model
CMA: will implement EUMETSAT approach (with a different smooth approach, based on a Gaussian filter)

18. DCCs
Update frequency  Different purposes = Quick jump detection in time series / reducing noise (climate application)
Impact on the definition of a VIS/NIR GSICS product as noise reduction implies further processing
Further testing on deseasonalisation methods (EUMETSAT/NOAA/CMA)
For consistency, similar processing to the reference  Can be tested by EUMETSAT on MODIS reference data set
Preparation of a demo product for 2015 for VIS06 and NIR16 (?)
What about VIS08? MODIS saturates!
Alternative = VIIRS
Needs for defining a method to move from Aqua MODIS to NPP VIIRS (similarly to the IR)  Action on NASA

19. Technical Tour of IMD Satellite Centre

20. Lunar Calibration
ISRO, JMA and KMA presented updated results using GIRO.
Very large amount of Himawari-8 acquisitions  Useful for preparing MTG/FCI
Main discussions:
GIRO and GLOD policy + infrastructure set-up  need another iteration to take comments and suggestions on board. Deadline = May 2015
Moving towards inter-calibration (using Aqua MODIS / NPP VIIRS as references)
Uncertainty analysis still to be addressed

21. Lunar Inter-Calibration
A plan was presented with the list of actions to be addresses:
Estimating the over-sampling factor
Drift correction
Accounting for spectral differences between instruments
Establishing an absolute scale for lunar calibration
(Medium and long term activities on lunar calibration)
EUMETSAT will commit to all of them (E. is for the moment addressed only by an action on SWG to identify user requirements).
Spectral differences between instruments: validation of the estimates derived from GIRO, using hyper-spectral instruments with Moon observations (GOME-2, Hyperion, SCIAMACHY)
 Some activities covered by an external study

22. Overview Highlights of 2015 Annual Meeting Other progress in 2014/15
Sub-Group News
Issues for Executive Panel & GSICS Users
Potential Future GSICS Deliverables
GRWG Chair & Vice-chair
2016 Annual meeting
Issues for GSICS Users

23. Inter-Calibration Product Development for Geostationary Imagers
In 2015 we will have GSICS Corrections for all IR channels of current geostationary imagers
(excluding ROSHYDROMET)
Started planning impact assessments
In 2015 we will have first GSICS Corrections for VIS channels of some current geostationary imagers
Based on Deep Convective Clouds
Developing lunar inter-calibration algorithm
Will combine results from both methods

24. Making GEO-LEO IR Operational
Action: Tim to cooperate with the GDWG to develop a version control document [Closed]
Action: Manik Bali to review User Guide for SEVIRI-IASI products [Closed]
Action: EUMETSAT to update the GEO-LEO IR ATBD and operational implementation to inflate the coefficient uncertainties to obtain consistency with time series estimates of the random component. 
Recommendation: all GPRCs to consider the update of the GEO-LEO IR ATBD in their uncertainty assessment following the EUMETSAT example of adjusting uncertainty estimates to obtain consistency with time series statistics.  

25. Overview Highlights of 2015 Annual Meeting Other progress in 2014/15
Sub-Group News
Issues for Executive Panel & GSICS Users
Potential Future GSICS Deliverables
GRWG Chair & Vice-chair
2016 Annual meeting
Issues for GSICS Users

26. Microwave Sub-Group – UPDATE!!
Web meetings – not at annual meeting
Could be good for JAXA?
Need to establish link to Users
Special Session at microwave conference?
Following discussion on GSICS deliverables
Algorithms for FCDRs

27. UV Sub-Group New Chair of UV Sub-Group : Rosemary Munro
Within the framework of Atmospheric Composition Group activities:
CEOS WGCV: Support to the preparation of a workshop on sensor on-ground and in-orbit (no-vicarious) calibration. Proposal for joint meeting presented to WGCV in May
Contribution to the inter-comparison between the OMPS and GOME-2 Sensor Data Record/L1b by Wu et al. (presented at the 2014 EUM User Conference)
Prototyping inter-calibration procedure GOME-2/MSG (VIS06) and GOME-2/AVHRR channel 1.
Preparing for routine AVHRR-GOME-2 and IASI sensor inter-calibration within operational PMAp EPS multi-mission sensor colocation and co-registration framework  Potential for producing time series of AVHRR Ch1(2)/GOME-2 and AVHRR T4/5/IASI inter-calibration coefficients.

28. GSICS Organisation CGMS WMO GSICS Exec Panel GSICS Coordination Center
GSICS Research Working Group
UV Sub-Group
CEOS ACC
WGCV ACSG
VIS/NIR Sub-Group
WGCV IVOS
IR Sub-Group
Microwave Sub-Group
WGCV MWSG
GPM X-CAL
GSICS Data Working Group

29. Overview Highlights of 2015 Annual Meeting Other progress in 2014/15
Sub-Group News
Issues for Executive Panel & GSICS Users
Potential Future GSICS Deliverables
GRWG Chair & Vice-chair
2016 Annual meeting
Issues for GSICS Users

30. Definition of GSICS Deliverables
Agreed on terminology:  
GSICS Deliverables include GSICS Products, Tools, Algorithms and Documents:  
GSICS Tools for use by inter-calibration developers, (GIRO, SBAF, …)  
GSICS Products for users of satellite data, including calibration corrections/coefficients  
GSICS Algorithms, which describe inter-calibration processes, (described by ATBD)  
GSICS Documents, including Guidelines, Reports, …  
GSICS Recommended Standards, including Solar spectrum, …  
See Jerome’s presentation on Item 6 for more details

31. Potential Future GSICS Deliverables
Decision: Retrieved SRFs could be considered as a GSICS Product, if they are derived on an ongoing basis, as a result of inter-calibration. However, it was recognised that adjustments can be made during commissioning as a result of GSICS algorithms and it would be difficult to review these through the GPPA on a useful timescale. 
Recommendation: The PIs of inter-calibration algorithms are encouraged to attend the annual GRWG/GDWG meeting. 
Action: GRWG Chair to add a meeting on NWP in the agenda of the next GSICS web meetings in 2015/2016.
Actions: NASA to investigate the use of MIIC to generate data for near-real-time processing of DCC using VIIRS and potential to transfer the MIIC technology to other data centres. 

32. Overview Highlights of 2015 Annual Meeting Other progress in 2014/15
Sub-Group News
Issues for Executive Panel & GSICS Users
Potential Future GSICS Deliverables
GRWG Chair & Vice-chair
2016 Annual meeting
Issues for GSICS Users

33. Routine Generation of GSICS Products
12 November 2018
Routine Generation of GSICS Products
Decision: GSICS should aim to provide users with the most recent available calibration data
at the highest available update frequency,
allow users to decide how to apply it for their applications.
For example:
users interested in trends may not want artificial jumps in the calibration time series, which could be avoided by applying frequent calibration updates
near-time applications may want to minimise additional calibration noise by using the most accurate, stable calibration.
Action: Tim to propose this approach (issuing frequent GSICS corrections) to the Exec Panel and Users Workshop.

34. Requirements for generating FCDRs
Rob provided a preliminary review of the inter-calibration requirements for various climate application project
Action: EUMETSAT to circulate Rob’s review of FCDR inter-calibration requirements to GRWG/GDWG,
identifying which type of inter-calibration product could meet each of these.
Action: GCC to review these FCDR inter-calibration requirements
in the framework of the GSICS User Product Guidance, to identify where common inter-calibration types, which are not specialised to specific applications, and report to GRWG. These could be considered as potential future GSICS products.

35. 2015 GSICS Users Workshop At EUMETSAT Conference
At MeteoFrance, Toulouse,
22 September :00-17:30
Collocated with SPIE European Remote Sensing Conference
Introductions to GSICS
and its deliverables
Soliciting input from potential users on GSICS products
Managing User Expectations
International Conference Center of the Météo-France Campus

36. 12/11/2018
Conclusions
GSICS is maturing into a system for generating inter-calibration products
Suitable for integrating into operational processing
First products soon to be declared operational
Continuing to develop new inter-calibration products
While cooperating with related activities
To integrate GSICS into WIGOS
To support Architecture for Climate Monitoring from Space

37. 12/11/2018
Thank You 41